The present invention relates to sash windows and in particular to a mounting for the spring tensioning arrangement used in such sash windows.
Modern sash window arrangements utilise flat coiled ribbon springs which are arranged to unwind as the sash is slid and moved within a window frame. The coiled springs provide a counterbalancing force to counterbalance the weight of the sash window thereby making movement, and opening of the window easier. Typically the coiled springs are mounted, via a mounting arrangement, within a vertical channel section of the window frame or jamb. A free end, referred to as a tail, of the spring is connected to a sash shoe slidably mounted within the channel section of the window frame. The shoe in turn is then connected to the sash window jamb, usually towards the lower portion of the sash window.
The coil springs are generally of a constant tension type in which the outer profile of the coil itself is rotatably held and supported within the mounting whilst the other free end of the spring is free such that the coil spring can rotate as the spring is unwound and the tail is extended. To provide sufficient force to counterbalance the weight of the sash window multiple springs may be provided with the free ends or tails connected together.
An example of a prior arrangement, as generally described above, for a mounting for multiple springs for use in a sash window is described in U.S. Pat. No. 5,365,638. As described in this prior patent, individual mounting means are provided for each of the coil springs. The spring mounting comprises two parallel arranged upstanding wall portions with a coil spring support element interconnecting these wall portions. The coil spring is inserted in between the wall portions with an outer coil surface of the spring supported and resting on the coil spring support element/surface. To provide a multiple spring assembly a number of individual mounting means are provided and stacked into an assembly in the window jamb.
Whilst this mounting arrangement, and similar prior arrangements, provide a practical method of mounting and supporting the springs, there are a number of problems with such an arrangement and the mounting arrangement can be improved generally. Particular problems are that the individual mounting for the springs are relatively complex and involve a number of different components. This increases production costs. The individual mountings also have to be installed individually and/or assembled which increases assembly time and costs. Installation of a stack of mountings within the channel section can also in practice be difficult. The installation of the sash shoe can also be problematic, in particular due to the applied tension of the springs which are attached to them. The correct lateral location of the prior mountings within the channel section and alignment of mounting can also be difficult especially due to the restricted access to the channel section. The stack of mountings, secured to the jamb via a single screw fitting also have a tendency to undesirably bow under the tension of the springs. If multiple screw fasteners are used to reduce this bowing then assembly time is increased. It has also been found that dirt can accumulate within the mounting assembly and springs. This can adversely affect performance and operation of the counterbalance. The prior art mountings also obstruct the channel section within which the tilt latch is engaged to locate the sash. Consequently the prior art mountings have to be carefully positioned within the jambs such that opening of the window is not restricted.